In the art of catalytically hydrolyzing acrylonitrile with water to acrylamide, various copper and copper containing catalysts have been proposed, such as mixtures of copper oxide with other metal oxides, reduced copper oxide/metal oxide mixtures, copper and copper/metal mixtures (see U.S. Pat. Nos. 3,597,481; 3,631,104; 3,642,894; and 3,642,643.) The use of Raney copper catalysts for this purpose is shown in German Pat. No. 2,036,126, German DOS No. 2,164,185 (1972), and Canadian Pat. No. 899,380 (1972). Based upon the method of catalyst preparation, it would appear that such prior art can be cataloged into two groups, one group involving the reduction of a copper containing compound or compounds, the other group involving the activation of a copper or copper alloy (such as Raney copper).
So far as can be determined, when using a Raney copper catalyst to hydrolyze acrylonitrile to acrylamide by the teachings of the prior art, it has been the practice to prepare or activate such catalyst by contacting such in a particulated form solely with aqueous caustic to dissolve away at least a portion of the aluminum after which the resulting activated product is kept under water or inert solvents to avoid oxidation. Apparently complete aluminum removal was heretofore sometimes believed to have been achieved and to be desirable for purposes of enhancing catalyst activity for this intended hydrolysis reaction; see, for example, the above referenced Canadian Pat. No. 839,384 at p. 5 where the Kawaken Fine Chemicals Co. Raney copper catalyst is used. According to Kawaken Fine Chemical Co. trade literature, it appears that substantially complete aluminum removal is achieved.
The art theorizes that Raney catalysts can contain amounts of insoluble aluminates which are sufficient to adversely affect catalyst activity and life for whatever reason, and the art has described efforts to remove such impurities; see, for examples, U.S. Pat. Nos. 2,673,189; 2,604,455; 2,950,260; and British Pat. Nos. 642,861 and 658,863. Apparently, no one has ever heretofore used a catalyst so prepared as to minimize the presence of alumina for catalytically hydrolyzing acrylonitrile to acrylamide under aqueous liquid phase conditions.
It has heretofore been proposed to activate Raney alloys for use as fuel cell electrodes by using in the activating solution alkali metal tartrates or lower aliphatic amino compounds; see U.S. Pat. No. 3,235,513. See also U.S. Pat. No. 3,067,276 for a discussion of catalyst regeneration. No one has ever heretofore prepared a Raney copper catalyst so activated in the presence of an additive and then used such a catalyst to catalytically convert acrylonitrile to acrylamide under aqueous liquid phase conditions.
Because of the limitations and short-comings observed for prior art Raney copper catalysts, the art continues to seek a Raney copper catalyst adapted for use in such hydrolysis reaction which has a high initial activity and a long activity life. In particular, the art desires such a catalyst which is particularly well suited for hydrolyzing acrylonitrile to acrylamide using a concentrated acrylonitrile/water feed and employing a rapid conversion rate while achieving a high conversion level.